Inner tube for pneumatic tires.



N. H. SHAW.

INNER TUBE FOR PNEUMATIC TIRES.

APPLICATION FILED MAYZB 1917.

I QWAQQ mmweb. 26, 19m

NTEIANEL SHA'W, DE? BOSTGT, vIASSLHUSETTS.

Specification of Itetters Eeteut.

Application ied May 2S, i917. Serial Eo.' f. A

To @ZZ 'Lu/wm if may Concern:

Be it known that I, NATHAMEL H. SHAW, :i citizen of the United States, residing et "ioston, count'v of Suiiolk, Stoute or Messucliusetts. have invented un improvement in inner Tubes for Pneumatic Tires, of which the following descriiitiou, in connection with the accompanying drawing, is o speciiication` like characters on the drawing representierY like ports.

This invention relates to inner tubes for pneumatic tires und hes for its object to provide un improved inner tubeivhicli will be seit-seating in cese it becomes punctured. l propose to accomplish this by making the inner tube in two Sections which he ve :i couccutric relation to euch other so tti-et one of the tube sections is situated 'Within the other :1nd by so constructing` seid tube sections tirol; iviicn the inner tube iniiuted und thereby subjected to internal pressure, a zone viii be foi-nud in tire body oi' 'the inner tube in which the iuuieriui reoit is subjected to compression in zi direction at right angles io u. radial line. As o result, vviienever the inner tube is punctured und the puncturing implement is Withdrawn, the internal stresses nt this zone. in the inner tuoe wiii close the puncture und Prevent the escupe ot the air. This zone in which the material of 'tlie inner tuoe is subjected to compression in u direction :it right angies to e redini line nuiv be crested in various uurs, out preferably by providing` the outer face of the inner tube section with ti-siisped grooves und ivedge-slniped ribs which pret'- eruiilv lieve flattened or rounded spices und b v providing the inner fece of the outer tube section with cor espondingly-slioped ribs and grooves. the ribs oi? euch section being received in the grooves of the other section. Giving' to the fact that the ribs iiuve iiettened spices and to the further feet tiretthe ribs und `grooves are Wedgesiieped in crossscction, the air pressure in die intia'ted tire will torce the ribs into the grooves with o wedging action7 thus producing the desired zone of transverse compression.

n order to give en understanding of my invention, lieve illustrated in the drawings some selected embodiments therein2 which will non7 be described1 after which the novel :features ivili oe pointed out in the appended claim.

Figure l is a View showing' one Way in tube embodying my invention which rny improved inner tube mede;

Fig. Q is e, sectional view through en inner may be Fig. 3 is e similar view through on inner tube showing e, different embodiment of my invention;

Fig'. is e side View of an inner tube heving the construction shown in Fig: 3;

rig. is a. simiisr vieuT ot en inner tube having the construction shown in Fig. 2;

Fig'. 6 is an enlarged sectional view showing the construction illustrated in Fig. 2.

fis stated above, my improved inner tube comprises two tube sectionsq v'one of which is situated within the other and which for convenience will hereing'tfter be referred to os the inner tube section and the outer tuoe section. n 25 for instoncefwiiicii. is transverse section of en inner tub-e erfroodi ing; my invention, the outer tube section indicated et i and the inner tube section et tlie, inner die section being piso-ed Within die outer tube section. Each tube section is i'orined on the fece thereof which has engage-nient with tlie other tube section with ribs and grooves that fit corres@ending grooves and ribs in the fece oi the otiier'section. For instance, lin the construction shown in Fig. 2, the inner tube section 2 is provided on its outer foce with e plurality of rios 3 and with grooves formed between the ribs, and the outer tube section 1 is provided on its inner 'trice with e plurality of ribs 5 and grooves G formed oetveen the ribs 5. 'Tire ribs on the outer tube section l ere constructed to iit the grooves e formed on the inner tube section 2, and siinilfirlf,r tire ribs 3 on the inner tube section :ire constructed to iit the grooves 6 formed in the outer tuioe section 1. These ribs and grooves univ extend either loiwitudinoiiv ot 'the tire or circumi'erentieiiy thereof and they lieve :inv suitable shape---- Wiii preerubiy, however, make the grooves ishaped, and ineke the rios of o corresponding shape. In Fig. 2 the ribs and grooves extend iongitudinelly of die tire, und in Fig. 5, e, part of on inner tuoe is shown in which o portion of outer tuoe section is turned beek, es shown et 7, to better iiiustrete the construction of the rios and grooves.

The rios 3 and 5 ere formed with rounded or iettened lspices, as shown in f. As s resut there vviii exist a space 'between the apex of each rib and the bottom oit thelv groove which it occupies. When the tubeis placed in the tire casing and is iniated to the proper pressure, ,the internal pressure -to compress each rib in the groove in Which it Was received, thus creating Within that portion of the body of the inner tube occupied by the ribs and grooves a pressure in a direction at right angles to a radial line, the degree of pressure depending somewhat on the shape of the ribs and grooves and on the internal air pressure Within the inner tube.

Owing to the fact that the ribs are flattened or rounded, there Will exist a space between the apex of each rib and the bottom of the groove it occupies, and hence there will be a continuing Wedging action which develops lcompression in 'a direction at right angles to a radial line because the eutire'pressure of the air willbe transmitted through the Wedging sides ofthe ribs and grooves. If an inner tube having ythis construction should become accidentally punctured, this pressure which is thus created in a direction transverse or at right angles to a radial line will operate to close the puncture and thus prevent the escape of air.

In Figs. 3 and i I have shown an embodiment of the invention wherein the grooves and ribs run circumferentially of the tire. nthis embodiment, the ribs, on the outer tube section 1 are designated 50; the grooves in the inner tube section which receive the ribs are designatedeO; the ribs on the inner tube sect-ion arc'designated 30, and the grooves in the outer tube section which receive the ribs 30 are designated 60.

The Isame result will occur from the arrangement of grooves shown in Figs. 3 and si. as that shown in Figs. 2 and 5. The inner tube embodying my invention may be made in various ways. The advantage of forming the ribs 3 and 5 with the rounded points 8 is that thisconstruction prevents a space betiveenf the point of eachrib and the bottoni of the corresponding groove so that when the inner tube is subjected to internai pressure, the ribs will Wedge into the grooves more effectively than if thc'point of each rib had engagement with the bottom ci the corresponding 4groove. ln Fig. l have shown two sheets or strips ll and l2, each having ribs and grooves formed on one face thereof. These sheets or strips Wili be made of rubber, and to make the inner tube, they may be placed so that the ribs of one sheet will fit the grooves of the other sheet and then the two sheets thus combined may be rolled up into tubular shape and the edges secured together in ang.7 usual way. in this Way a tube of the proper length can be made, after which the ends of? the tubes may be brought together and ce mented and vulcanized to each other.

The tube sections shown in Figs. 2 and 5 may be made in the same Way that ordinary inner tubesare made by simply using' dies having fluted faces to provide the necessary iiuted faces on the tube sections.

I claim:

A pneumatic tire comprising two tube sections,rone seated within the other, each scction having grooves formed in the iace thereof which engages the other section and also having ribs thereon to enter the grooves of the other section, the bottom of the lgrooves being substantiallyv 'ii-shaped and Vthe apex of the ribs rounded, whereby a space will exist between the apex of each rib and the bottoni oit the groove it occupies, thus effecting a Wcdging action between the ribs of the opposing tube sections.

in testimony whereof` have signed my name to this specification.

vNHANlli H. SHVV. 

